Improvement in preparing metallic patterns for casting



UNITED STATES PATENT FFICE.

THEODORE G. BUOKLIN, OF WEST TROY, NEW YORK.

IMPROVEMENT IN PREPARINGfMETALLlC PATTERNS FOR CASTING.

To all whom it may concern Be it known that I, THEODORE GnBUCKLIN, ofWest Troy, in the county of Albany and State of New York, have inventeda new and Improved Mode of Finishing Cast-Iron Patterns for the Use ofFounders and for other purposes, of which the following is a full andexact description.

The nature of my invention consists in converting the surface of ironcastings into plumbago by treating them with dilute acid, whichdissolves out most of the iron, but leaves the carbon, which isinsoluble in the menstruum, in the form of graphite or plumbago, which,when dry,is capable of being smoothed and polished, so as to make itsuitable for the surface of patterns and for the protection oftheinterioriron from oxidation. Preparatory to operating upon thecastings a tub or other convenient vessel is provided of the propersize, in which is placed asuitable quantity of dilute sulphuric or otheracid, or a mixture of acids, in the proportion of one part of the acidto about ten parts of water. lt is to be observed that for this purposethe proportion of the acid must not greatly exceed that above given,because its action would then be too energetic and it would corrode thesurface of the casting unequally, and thus render it unfit for apattern. Into this menstruum the castings are placed and allowed toremain undisturbed for a space of time varying from one to forty-eighthours, according to the thickness which the coating of plumbago isrequired to be made. If the surface of the casting should happen to beuneven, and it is required to reduce it to a uniforrnly even and trueplane, the depressions should be insulated from the action of the acidby means of a coating-of beeswax or other substance capable of resistingthe action of the acid, and the protuberances then subjected to itsaction until sufficiently reduced, when, if the thickness of the entirecasting were required to be lessened, the wax might be removed and thewhole surface subjected to the action of the acid by immersing it in thetub. When this part of the process has progressed to the required pointthe further action of the acid is arrested by dipping the casting into astrong solution of potash or other alkali,after which it is carefullydried by a fire or in an oven prepared for the purpose. The next step isto remove by means of a knife, scraper, chisel, or plane so much of theprotuberant or other parts as may be deemed necessary, and then with asmooth piece of steel or other hard substance of the proper shape leveland burnish the whole surface, which will then be in the best possiblecondition for a pattern to be molded from,and thus obviating thenecessity of using either wax or varnish.

What I claim in the before-described process as of my invention, anddesire to secure by Letters Patent, is.-

Oonvertin g the surface of iron castings into plumbago by treating themwith dilute acid, and then reducing them to the required form and sizeand smoothing and polishing them, substantially in the manner and forthe purpose herein set forth.

THEODORE G. BUOKLIN.

Witnesses:

Fas. BoNRAsso, MIRANDA MARTIN.

